In one class of control valve assemblies, a valve member is moved between upper and lower valve seats during its actuation cycle. For instance, in many hydraulically actuated fuel injectors, a control valve assembly includes a control valve member that is moved between upper and lower conical valve seats by a solenoid and a biasing spring. Although the control valve member moves a distance on the order of only about several hundred microns, the valve member can have a substantial velocity when it impacts one of the seats.
It is usually undesirable to have the valve member linger for any substantial length of time in between the upper and lower valve seats. Thus, relatively high accelerations and velocities are usually desirable when moving the valve member from one seat to the other. However, it is also typically desirable to have impact velocities that do not cause unnecessary damage to the valve seats nor cause undesirable noise.
In most cases, damage to the valve seats can be reduced by an appropriate design and by the use of suitable materials, but not eliminated entirely. Wear to the valve seats will degrade fuel injector performance overtime, and may eventually lead to failure of the unit.
Moreover, the problem of reducing noise produced by impact of the valve member on one of its seats can often prove problematic. While noise often does not undermine the performance of a valve assembly, a consumer may perceive a problem due to the presence of noise. This noise usually reveals itself as a loud clicking that is not only annoying, but often undermines a users confidence in the valve, because the noise sometimes lends one unfamiliar with a given system the impression that the valve is not working properly.
The invention is directed to addressing one or more of the above concerns.